Rack-mounted printed circuit boards (PCBs) are used in a variety of applications because they are more compact and generally less expensive than boards that are incorporated into an enclosure or stand-alone case. While rack-mounted PCB assemblies are compact, they also have certain structure limitations, and are more prone to damage.
For example, it is common for a faceplate to be attached to one edge of the board, with the faceplate including some form of handle to allow a user manipulation of the assembly. Because of the resulting “L”-shaped structure, an unsatisfactory level of bending stress can arise at the interface of the board and the faceplate when the board is inserted and removed from the rack. This is particularly a problem in rack-mounted boards such as vehicle detector boards that require frequent maintenance, calibration, or re-configuration.
Furthermore, such rack-mounted board assemblies are often incorporated into field cabinets (e.g., traffic cabinets) that are subject to external weather conditions. Rapid temperature extremes can reduce the reliability or even cause damage to the components on the board. In addition, many electronic components are temperature dependent—that is, one or more of their electrical characteristics are a strong function of ambient temperature.
Another issue with prior art board assemblies is that such boards typically include switches, dials, sliders, or other actuatable components that are adjusted by the technician during setup and maintenance. This requires separate cards, printouts, or other forms of written instructions to be included with the board to assist the technician. Because space is often a premium in rack-mount systems and cabinets, there is very little room to store such written material. And even if it were to be stored or otherwise provided to the technician, the variety of boards appearing in a finished cabinet makes it impractical to quickly find an instruction card for a particular device.
Accordingly, there is a need for board assemblies that overcome these and other limitations of the prior art.